Problem: Simplify the following expression: ${-9(-k+1)+2(-5-2k)}$
Answer: Distribute the ${-9}$ into the first set of parentheses: $ {-9(}\gray{-k+1}{)} + 2(-5-2k) $ $ {9k-9} + 2(-5-2k) $ Distribute the ${2}$ into the parentheses: $ 9k-9 + {2(}\gray{-5-2k}{)} $ $ 9k-9 {-10-4k} $ Rewrite the expression to group the ${k}$ terms and numeric terms: $ {9k - 4k} {-9 - 10}$ Combine the ${k}$ terms: $ {5k} {-9 - 10}$ Combine the numeric terms: $ {5k} {-19}$ The simplified expression is $5k-19$